Effect of the Concentration and Nature of the Emulsifying Agent on the State of Dispersion of Latexes

1954 ◽  
Vol 27 (2) ◽  
pp. 468-471 ◽  
Author(s):  
A. I. Yurzhenko ◽  
V. P. Gusyakov
Keyword(s):  
Emulsion Polymerization ◽  
Systematic Study ◽  
Scientific Literature ◽  
The State ◽  
Experimental Conditions ◽  
Latex Particles ◽  
Potential Value ◽  
Polymeric Particles ◽  
Emulsifying Agent ◽  
Butadiene Polymerization

Abstract Yurzhenko and Mintz were the first to show that, in the process of emulsion polymerization, the size of the polymeric particles in the latex increases regularly. This phenomenon is in complete accord with the theory that, in the particular case of 1,3-butadiene, polymerization proceeds to a major extent in the micelles of the emulsifying agent. A systematic study of the state of dispersion of synthetic latexes in its relation to the experimental conditions and the processes taking place during their formation would appear to be of great potential value in the study of the mechanism of emulsion polymerization. The present authors have studied the degree of dispersion of synthetic latexes prepared in the laboratory, with different concentrations and types of emulsifying agents. Work in this field has not been reported in the scientific literature, although, in studies of emulsion polymerization, data on the state of dispersion of latexes under certain conditions have been reported. In the present work, the effects of other factors, such as the nature of the monomer, initiator, and electrolytes, on the size of the latex particles and the characteristics of these particles also were studied.

PLANEJAMENTO FAMILIAR COMO ASSUNTO DE MULHER!? PERFIL DE GÊNERO NA PRODUÇÃO CIENTÍFICA NO BRASIL

2019 ◽  
Vol 8 (1) ◽  
pp. 221-235 ◽  
Author(s):  
Daniella De Paula Chiesa ◽  
Mário Antônio Sanches ◽  
Daiane Priscila Simão-Silva
Keyword(s):  
Family Planning ◽  
Scientific Literature ◽  
State Of The Art ◽  
Health Sciences ◽  
Scientific Production ◽  
The State ◽  
Review Of The Literature ◽  
The Subject

O estudo do Planejamento familiar, no contexto da bioética, abre-se para diversas perspectivas, entre elas a valorização dos seus diferentes atores. Situado neste contexto o artigo tem como objetivo identificar o perfil de gênero na produção científica sobre Planejamento Familiar no Brasil, entre 2000 e 2014, assim como a área de formação e especialização dos autores. Foram utilizadas metodologias que permitiram mapear o estado da arte do tema estudado, a partir de uma revisão da literatura. O resultado da pesquisa identifica que a produção científica sobre Planejamento Familiar no Brasil se compõe de perfil destacadamente feminino (71,76%). Dos 73 artigos analisados, 42 (57,53%) o foco do tema está direcionado à mulher assim como evidencia-se a área de ciências da saúde com maior concentração das publicações do tema.  Este aspecto da pesquisa abre para uma realidade complexa onde se buscam criticamente as razões para a pesquisa em Planejamento Familiar ter ênfase na mulher e ser um tema de relevância nas ciências da saúde.Palavras-chave: Produção científica, Planejamento Familiar, Gênero.  ABSTRACT: The study of Family Planning, in the context of bioethics, opens to diverse perspectives, among them the appreciation of their different agents. Situated in this context the article aims to identify the profile of gender in scientific literature on Family Planning in Brazil, between 2000 and 2014, as well as the area of training and specialization of the authors. Methodologies were used which allowed to map the State of the art of the subject studied, from a review of the literature. The results found identify that the scientific production on Family Planning in Brazil is formed with a outstandingly female profile (71,76%). Of the 73 articles examined, 42 (57.53%) the focus of the topic is directed to women as well as showing the health sciences area with highest concentration of publications. This aspect of the research opens to a complex reality where we seek critically the reasons for Research in Family Planning have emphasis on woman and be a topic of relevance in health sciences.Keywords: Scientific Production, Family Planning, Gender.

scholarly journals Synthesis of double-responsive magnetic latex particles via seeded emulsion polymerization using macroRAFT block copolymers as stabilizers

2020 ◽  
Vol 11 (3) ◽  
pp. 648-652 ◽  
Author(s):  
Thiago Rodrigues Guimarães ◽  
Muriel Lansalot ◽  
Elodie Bourgeat-Lami
Keyword(s):  
Block Copolymers ◽  
Emulsion Polymerization ◽  
Magnetic Response ◽  
Seeded Emulsion Polymerization ◽  
Latex Particles ◽  
Magnetic Carriers

We report the synthesis of magnetic latex particles decorated with double-responsive PDMAEMA segments with fast magnetic response via RAFT-assisted emulsion polymerization, highlighting this strategy as a powerful tool for magnetic carriers design.

Treatment Following Progression in Metastatic Melanoma: the State of the Art from Scientific Literature to Clinical Need

2021 ◽  
Vol 23 (7) ◽  
Author(s):  
F. Serra ◽  
S. Barruscotti ◽  
T. Dominioni ◽  
A. Zuccarini ◽  
P. Pedrazzoli ◽  
...  
Keyword(s):  
Metastatic Melanoma ◽  
Scientific Literature ◽  
State Of The Art ◽  
The State

Entry of free radicals into latex particles in emulsion polymerization

1991 ◽  
Vol 24 (7) ◽  
pp. 1629-1640 ◽  
Author(s):  
Ian A. Maxwell ◽  
Bradley R. Morrison ◽  
Donald H. Napper ◽  
Robert G. Gilbert
Keyword(s):  
Free Radicals ◽  
Emulsion Polymerization ◽  
Latex Particles

Smart polymeric particle encapsulated gadolinium oxide and europium: theranostic probes for magnetic resonance/optical imaging and antitumor drug delivery

2016 ◽  
Vol 4 (6) ◽  
pp. 1100-1107 ◽  
Author(s):  
Ruiqing Liu ◽  
Shuang Liang ◽  
Cun Jiang ◽  
Li Zhang ◽  
Tianmeng Yuan ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Magnetic Resonance ◽  
Optical Imaging ◽  
Emulsion Polymerization ◽  
Gadolinium Oxide ◽  
Antitumor Drug ◽  
Ph Responsive ◽  
Polymeric Particles ◽  
Polymeric Particle

Paramagnetic, luminescent, and temperature/pH-responsive polymeric particles with MR/optical imaging and antitumor drug delivery capability are prepared by emulsifier-free emulsion polymerization.

The State of Polydispersion of Hevea Latex. I

1946 ◽  
Vol 19 (1) ◽  
pp. 176-186
Author(s):  
J. H. E. Hessels
Keyword(s):  
Protein Content ◽  
Hevea Brasiliensis ◽  
The State ◽  
Rubber Content ◽  
Rubber Latex ◽  
Latex Particles ◽  
Rubber Particles ◽  
The Subject ◽  
Points Of View ◽  
Good Agreement

Abstract The rubber particles in the latex of Hevea brasiliensis are present in the form of a polydispersion, and their diameters lie within the range of 0.1 to 3 microns. The rubber hydrocarbon itself is composed of a mixture of macromolecules of different degrees of polymerization. Rubber latex is, therefore, a system which is at the same time both polydispersed and polymolecular. It is well known that the degree of dispersion of a substance governs to a great extent certain properties of the substance. Moreover, astonishing as it may seem, in the great number of investigations which have been made of the composition and properties of latex and crude rubber, almost no attention has been paid to the part which may be played by the dimensions of the latex particles. However, in an investigation concerned with the centrifugation of latex, Loomis and Stump have called attention to this possibility, and in a study of latex obtained by fractionation, and in which the majority of the latex particles were of large dimensions, McGavack came to the conclusion that the protein content is proportional to the surface area of the globules. This limited knowledge of the subject seemed to warrant a more thorough study of the problem, which is of fundamental importance both from the theoretical and practical points of view. The investigation as a whole divided itself into three essential parts: (1) separation of latex into fractions containing particles of different sizes, and measurement of the state of dispersion in these fractions, (2) a study of the relation of these fractions to the composition of the rubber, i.e., the relation between the content of nonrubber components and the size of the latex particles, and (3) a study of the changes in the properties of the rubber hydrocarbon with change in the size of the latex particles. The latex used in this investigation was ordinary latex, containing 38–40 per cent dry-rubber content and preserved with ammonia. For the most important points, a concentrated latex (creamed latex containing 60 per cent dry-rubber content) was also tested. These two latices were about two years old when the investigation was started, and they gave results which were in good agreement with each other. In the present paper, only the data obtained with the first of the two latices are presented.

scholarly journals POSSIBILITIES OF DEVELOPING INTERACTIVE E-LEARNING SYSTEM FOR BORDER GUARDS TRAINING IN THE STATE BORDER GUARD COLLEGE OF THE REPUBLIC OF LATVIA

2020 ◽  
Vol 3 (8) ◽  
pp. 45-53
Author(s):  
Mārtiņš Spridzāns ◽  
Jans Pavlovičs ◽  
Diāna Soboļeva
Keyword(s):  
Scientific Literature ◽  
Online Communication ◽  
The State ◽  
Learning Systems ◽  
Learning System ◽  
Digital Learning ◽  
E Learning ◽  
Research Findings ◽  
The Republic ◽  
Learning Development

Efficient use of educational technology and digital learning possibilities has always been the strategic area of high importance in border guards training at the State Border Guard College of Latvia. Recently, issues related to training during the Covid-19, have spurred and revived the discussion, topicality and practical need to use the potential of e-learning opportunities which brought up unexpected, additional, previously unsolved, unexplored, challenges and tasks to border guards training. New opportunities and challenges for trainers, learners and administration of training process both in online communication and learning administration contexts. In order to find out and define further e-learning development possibilities at the State Border Guard College the authors of this research explore the scientific literature on the current research findings, methodologies, approaches on developing interactive e-learning systems in educational contexts, particularly within the sphere of law enforcement. Based on scientific literature research findings authors put forward suggestions on improving the e-learning systems for border guards training.

scholarly journals Obowiązki konstytucyjne w państwach postradzieckich

Prawo ◽  
2019 ◽  
Vol 327 ◽  
pp. 219-229
Author(s):  
Rafał Czachor
Keyword(s):  
Legal Status ◽  
Scientific Literature ◽  
The State ◽  
Quantitative Character ◽  
Qualitative And Quantitative

Constitutional duties in the post-Soviet countriesThe duties, along with rights and freedoms, define the legal status of the person in the state. However, the scientific literature pays more attention to the rights and freedoms, since they are considered as more important. The following paper tackles the issue of constitutional duties in the post-Soviet republics. The investigation has both qualitative and quantitative character and presents results in a comparative way.

Statistics as Social Science

2020 ◽  
pp. 17-40
Author(s):  
Theodore M. Porter
Keyword(s):  
Nineteenth Century ◽  
Great Britain ◽  
Social Science ◽  
Systematic Study ◽  
State Policy ◽  
Natural Philosophy ◽  
The State ◽  
Statistical Thinking ◽  
History Of

This chapter discusses statistics as social science. The systematic study of social numbers in the spirit of natural philosophy was pioneered during the 1660s, and was known for about a century and a half as political arithmetic. Its purpose, when not confined to the calculation of insurance or annuity rates, was the promotion of sound, well-informed state policy. Political arithmetic was, according to William Petty, the application of Baconian principles to the art of government. Implicit in the use by political arithmeticians of social numbers was the belief that the wealth and strength of the state depended strongly on the number and character of its subjects. Political arithmetic was supplanted by statistics in France and Great Britain around the beginning of the nineteenth century. The shift in terminology was accompanied by a subtle mutation of concepts that can be seen as one of the most important in the history of statistical thinking.

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